The present invention relates to the field of photo finishing and, more precisely, a photographic copier which is also referred to as photographic printer or optical printer. Such a photographic copier serves the production of photographic prints in a photographic copier, films which, for example, were exposed in a photographic camera are projected onto photographic copier material (for example, photo paper).
The exposure of the copier material not always results in a satisfactory reproduction of the picture information captured on the film. An essential cause therefore is that the dynamic of the luminescence (Grayscaling) contained in the picture information to be depicted cannot be converted on the picture median. This is caused, for example, by the strongly reduced luminescence dynamic range of the photo paper compared to a photographic film. Furthermore, the sensitivities of the photo paper are dependent on the light used for the projection. All this must be taken into consideration for producing a photographic copy, for example, on photographic paper, in order to achieve a realistic reproduction on the photographic paper of the picture information captured with the film.
It is especially required for the achievement of a good copy quality that the brightness profile of the copy is manipulated. One reason herefore, for example, resides in that the brightness differences which are still recognizable by an observer of the original photographic picture information which forms the basis of the film (the original), are no longer recognizable for the observer of the photographic copy when these brightness differences are located in a dark or very bright region of the photographic copy.
In order overcome this disadvantage, photographic copiers or optical printers have been suggested which use a LCD matrix in the path of the exposure beam. The transparence of the individual elements of the LCD matrix and thus the intensity profile of the light incident on the photographic paper is controllable and the brightness profile can thereby be influenced.
Conventionally, LCD matrixes are used herefore which are also used in screens or displays. These LCD matrixes have a high number of elements and operate according to the polymerization principle. This means a polarization filter is switched in series before or after matrix and the polarization condition of the matrix can be changed by applying a voltage so that the polarizations condition is perpendicular or parallel to the polarization filter. A complete darkening by way of the matrix can be achieved therewith. Such a matrix is known from DE 28 20 965 and DE 40 40 498.
It is known from DE 43 08 864 to combine several closely adjacent elements to a group whereby one part of the element of the group are switched to bright and the other part of the group to dark. Depending on the ratio of the bright and dark elements, different Grayscales can be achieved.
The matrix described in DE 197 03 063 includes 1500 individually controllable Grayscale able points.
As already mentioned above, polarization effects are normally used for the LCD matrixes. A further example therefore is described in U.S. Pat. No. 3,926,520.
A disadvantage of the copier apparatus used in the conventional matrixes is the low degree of transmission of the matrixes. Because of the polarization filter alone, at least 50% of the light intensity are lost. In practice, the maximum transparency of the conventional LCD matrixes is less than 20%. This however means that the intensity of the illuminating means is used in the copier apparatus must be increased by at least a factor of 5 in order to compensate for the intensity loss because of the LCD matrix. The higher light power, however, causes a higher thermal load on the component of the copier apparatus and especially also the LCD matrix which absorbs a major portion of the light energy.
It is an object of the invention to provide a photographic copier apparatus, wherein the influencing of the brightness profile is possible by way of a matrix without the requirement that the intensity of the illuminating means must be significantly increased.
This object is achieved with the features of the independent claims. Preferred embodiments are apparent from the dependent claims.
The photographic copier apparatus according to the invention includes, of course, a light source which emits the light required for the exposure of the photographic original. Typically, lamps, such as halogen lamps, are used as light source. However, in accordance with the invention, laser diodes or light emitting diodes can also be used which further reduce the thermal load.
In accordance with the invention, light sources of different colour, for example, lamps, or light emitting diodes of different colour can be used which light can be additively superimposed.
For example, a blue, green and red lamp can be provided which are mixed, for example, by way of a system for the optical mixing of the green, blue and red light. An optical mixing system can consists, for example, of mirrors which are, transparent for two of the three colors and reflect the other one of the three colors. An example for such a mixing system is disclosed in DE 43 09 795 C2. When differently coloured light sources are used, the spectrum of the exposure light for exposure of the copier material can be changed and adapted to the respective situation by changing the intensity of the different light sources or changing the time during which the differently coloured light sources act on the copier material. The respective situation is influenced, for example, by the type of the original material or copier material used, or by the image information contained in the original. Based on data on the copier material, the original material and/or the image information contained in the film, the duration and/or intensity with which the light of a specific colour acts on the copier material can be controlled by way of a data processing arrangement in order to so achieve an optimal picture quality. Alternatively or in addition to the differently coloured light sources, colour filters can be provided as described further below. These colour filters can also be controlled on the basis of the above-mentioned data in order to so influence the spectrum of the light acting on the copier material with respect to duration and intensity of the individual colours.
The above mentioned coloured lamps, i.e. the blue, green and red lamp can be realized by way of a lamp which emits white light and which is combined with a colour filter which only lets red, green or blue light pass.
To guide the light from the light source to the photographic original, to shine it therethrough and to guide it to the light sensitive copier material, optical, light guiding, for example, light bundling or light scattering means, such as lenses, mirrors, shudders, partially transparent mirrors, compound lenses, collecting lenses, dispersing lenses, prisms and so on are provided.
In order to produce a desired brightness profile on the light-sensitive copier material, a liquid crystal matrix is provided in the light path which is shone through by the light before it impinges on the photographic copier material. The individual elements of the liquid crystal matrix may be controlled so that the transmission of the individual elements can be changed. A light intensity profile is thereby produced so that individual regions of the photographic copier material can be more strongly exposed than others. The brightness profile of the photographic copier material can thereby be manipulated in the desired manner in order to produce an optimal picture for the observer on the copier material.
The brightness profile is manipulated depending on the image information captured by the film. For example, regions which would become dark on the copier material without manipulation are brightened when thereby contrast or brightness scales become more clearly apparent in the dark region. In order to be able to use the captured image information for the manipulation of the brightness profile, it must be recorded and analysed prior to the control of the liquid crystal matrix, which preferably is a scattering liquid crystal matrix.
Conventionally, the recording of the image information for this purpose is carried out with a scanner which scans the photographic original (the film) before the latter is shown through for the production of a copy. Such a scanner is usually located in the photographic copier and is positioned along the transport path of the original material.
A separate scanner is usually provided for the production of index prints.
Index prints represent a collection of the pictures of a photographic original on a printout or a photographic copier material. The individual images are significantly smaller than the usual picture formats and usually have a lower resolution. This separate scanner is preferably provided for APS films (Advanced Photo System). In accordance with the invention, the scanning data which were intended for the production of an index print are now used as the data bases for a manipulation of the brightness profile by way of the liquid crystal matrix. The liquid crystal matrix is thereby preferably scattering liquid crystal matrix, but it can also be a common, especially polarizing matrix. In this case of a common matrix as well, the external scanner is preferably used as herein described. In this manner, a scanning by the scanner provided within the photographic copier, which was intended for the gathering of the image information for the brightness manipulation, can be dispensed with. This speeds up the throughput in the photographic copier. Because of the external scanner which is indented for the production of the index prints, the internal scanner can also be disposed with and, thus, the copier cost reduced. Alternatively, the internal scanner can also be used, for example, for conventional small picture films (for example, 24 mmxc3x9736 mm format), while the external scanner is used for APS films.
Preferably, the data from the external scanner are processed before they are used for the control of the liquid crystal matrix. A data processing device is preferably provided therefore between the external scanner and the photographic copier which device is preferably also positioned outside the photographic copier. This data processing device converts the data from the external scanner into a format which corresponds to the format of the internal scanner. For example, the resolution of the external scanner per image is typically significantly higher than the resolution of the scanner in accordance with the invention. The liquid crystal matrix preferably has a resolution of less than 1000 elements. The resolution which is provided by the internal scanner corresponds exactly or substantially with the element number of the liquid crystal matrix. However, this resolution is usually significantly higher with an external scanner for the production of index prints of sufficient quality. For this reason, the data processing device converts the resolution of the external scanner in such a way that it is compatible with the element number of the liquid crystal matrix. Adjacent image elements captured by the external scanner are preferably combined therefore in order to obtain a smaller image data amount adapted to the element number for the control of the liquid crystal matrix. During this combination, the individual, combined image elements can be weighted differently.
Preferably, the data processing device is also used to supply a possibly externally positioned device for the printing of the index prints with the scanning data required therefore. These scanning data or image data preferably have a higher resolution as the image data used for the control of the liquid crystal matrix.
Especially when the number of lines and columns of the image data elements captured with the external scanner are not a multiple of the elements of the liquid crystal matrix used for the copier, an adaptation preferably by way of mathematical algorithms is carried out which provides a continuous transition of the image elements. For example, averaging processes or weighting processes are used. Mathematical processes can also be used, for example, for a desired reduction and sharpness of the image date before they are used for the control of the liquid crystal matrix.
It is therefore a preferred variant of the invention that the scanning is not carried out in a single step within the copier apparatus together with the transport of the original material in the copier, but in a separate step for the scanning of the original material before the latter is fed into the copier apparatus. It therefore concerns a two step process, first the external scanning of the original material and then the processing of the original material within the copier apparatus.
The individual elements of the liquid crystal matrix are preferably positioned in one plane. The elements of the liquid crystal matrix are in the following, also referred to as image elements.
Conventionally, liquid crystal matrixes are used in photographic copier apparatus which allow in the locked condition an almost complete darkening. This allows the production of different Grayscales by combination of several liquid crystal elements to one group as described, for example, in DE 43 08 864. It is thereby a disadvantage that this type of matrixes has a low maximum transmission.
The inventors of the present application have discovered that the liquid crystal matrixes operating according to the scattering principle are well suited for the manipulation of the brightness profile despite their relatively low ratio between maximum and minimum transmission (contrast), namely of typically three. Although with such scatter matrixes, one can typically achieve at a maximum transmission of 80% only a minimal transmission of about 30% or at a maximum transmission of about 70% a minimal transmission of about 10%, but the contrasts achievable thereby have proven sufficient. An essential advantage over the conventional LCD matrixes which typically use the polarization effect is the high maximum but the also comparatively high minimum transmission as well the scatter effect. All this prevents a heating up of the matrix. The high transmission signifies a low absorption and thereby little heating up. The absorption itself is reduced compared to the conventionally used liquid crystal matrixes, since the matrix essentially does not absorb the light but scatters it, contrary to the polarizing matrix.
The high maximum transmission is promoted by a comparatively low element number of the matrix. The inventors of the present application have discovered that an element number of typically less than 2000 and preferably in the range of about 200 to 1000 is sufficient to achieve an optically pleasing manipulation of the brightness profile. Because of the low element number, the percentage surface portion of the electrical conductors on a matrix for the individual elements can be reduced, whereby the transmission is further increased.
It is a disadvantage of a low element number that the intensity profile produced by the different transmission of the elements of the liquid crystal matrix can produce brightness edges on the copier material which irritate the observer. For this reason, in accordance with the invention, the liquid crystal matrix is preferably optically unfocused projected onto the photographic copier material so that a smoothing of the light intensity profile produced by the liquid crystal matrix results.
A control of the total brightness can be carried out through the exposure time by way of a shutter. However, because of the high light transparency of the scattering matrix, it can be advantageous to attenuate the total light intensity in order to so avoid extremely short or also highly fluctuating exposure times. For this purpose, gray filters can be moved into the light beam. Preferably, the duration is adjustable during which the gray filters are moved into the light beam during the exposure process. Exposure times of roughly equal length guarantee a steady transport of the copier material and the original material in the printer.
Because of the highly scattering effect of the scattering matrix, the latter is preferably housed in an absorbing environment in order to prevent that scatter light reflected by the side walls circuitously reaches the copier material. Alternatively or additionally, the matrix is embedded in a diaphragm or diaphragm device which prevents that light separated from the matrix reaches the copier material. The diaphragm device, for example, can include several, serially positioned lines. For this, the matrix is preferably housed in a housing or light duct with light entry and light exit openings. In this housing or light duct, further openings are preferably provided for the electrical conduits for the control of the matrix. The inner walls of the housing or light duct are preferably constructed so that they absorb the scattered light.
The scattering matrix is preferably positioned before the photographic original so that the photographic original is shown through with the light intensity profile. The matrix is, however, not positioned directly before the photographic original (film). In order to avoid a focussed projection of the intensitive profile onto the photographic copier material, but at a preselected distance. A scatter disk is preferably positioned between the photographic original and the matrix. The scatter disk is preferably positioned as close as possible to the scatter matrix. It is especially preferred to integrate the scatter disk at the exit side into the above-mentioned housing for receiving the scatter matrix. Integrator plates or so-called honeycomb lenses are preferably used as optical elements for the culmination of the light.
A comb filter is preferably provided for the adaptation of the light used for the exposure to the spectral sensitivity of the copier material. It lets light within several preselected spectral windows pass with a respectively preselected intensity. For a similar purpose, a so-called balance filter or compensation filter is provided in the light beam which changes the spectral intensity distribution of the light and adapts it to the spectral sensitivity of the copier material.
Furthermore, colour filters are preferably provided which can be selectively inserted into the light path for a preselected time. In this manner, an especial adaptation to different copier materials or originals can be carried out. For example, if the photographic original requires an especial amount of red light, an exposure with only red light can be carried out for a preselected time before or after the exposure of the copier material in that the red colour filter is moved into the light path.
In order to achieve a liquid crystal matrix with a high maximum transmission, a liquid crystal matrix is preferably used which has a first transparent plate and a second transparent plate which are planar and spaced apart parallel to one another. A liquid crystal fluid is inserted between the plates which cannot escape from the intermediate space between the plates. At least one of the plates includes electrodes which can be supplied with control signals through feed conductors. In such a LCD arrangement, the first plate on a first side includes an electrode associated with a picture element, whereby the signal feed conductor for the electrode is conductor for the electrode is provided on the side opposite the first side of the first plate and whereby the electrode is connected with its associated feed conductor through a conductive region in the first plate.
It is thereby possible according to the invention to make the active surface of the individual picture elements exceptionally large, since no space must be spared for conductors connecting the electrodes of the picture elements with the feed conductors of the LCD arrangement. In this manner, a space between the electrodes of the picture elements is only required to prevent cross talk or short circuiting between the electrodes or the picture elements. Otherwise, if the feed conductors, as common in the prior art, were positioned on the same side as the electrodes of the picture elements, first, sufficient space would have to be provided also for the various feed conductors on the same side of a transparent plate and, second, respectively sufficient spacing would have to be provided between the various feed conductors and the electrodes. In this manner, the active matrix surface of the LCD arrangement would become so coarse that the structure of the LCD arrangement would be visible on the photographic paper upon exposure. Furthermore, such a reduction of the active surface causes a corresponding reduction in the achievable light intensity modulation. This is avoided in accordance with the invention.
Counter electrodes, separate from the electrodes are provided on the second transparent plate, as is known in principle. Between the electrode planes, the space with the liquid crystal fluid is provided for the generation of an electrical field to achieve a correlation or percolation among the crystal components of the liquid crystal fluids. Good results have been achieved when openings were formed in the first plate for the conductive regions, the edges or walls of which were at least partly covered or coated with a conductive material. The openings in the first plate can thereby be provided, for example, with a photographic mask and wet or dry etching techniques. A photo lacquer mask can be applied to the first plate for the formation of openings, which is insensitive to hydrofluoric acid. An etching with hydrofluoric acid then leads to the formation of openings, the edges or walls of which can then be coated with a conductive material by conventional techniques.
Especial advantages result when the electrodes or counter electrodes are made of a material which at least in the visible range of light is at least essentially transparent. It is also possible to form the electrodes and counter electrodes as conductor frames which surround the picture element regions or net-like cover them, however, such electrodes would lead to the generation of dispersion effects or the pattern of the LCD arrangement would be apparent on a print. Such a solution would also be associated with light loss and a reduced degree of modulation.
Accordingly, at least one of the feed conductors or feed conductor planes, which are associated with the electrodes or counter electrodes are manufactured from a material which is at least essentially transparent at least in the visible range of light. The same goes for the coating which within the openings in the first plate forms the conducting regions or passages.
A transparent material which can also be made conductive is ITO (indium tin oxide). This material can be applied evenly thin on a surface with conventional techniques, structured, and employed as a conductor which at the same time is essentially transparent for visible light.
It has been found especially advantageous when the transparent plates of the LCD arrangement in accordance with the invention are provided with a light or radiation sensitive additive, preferably a silver-containing additive, so that the conductive regions or openings can be produced with appropriate treatment. Correspondingly, transparent plates of glass are thereby provided with a mask which corresponds with the opening pattern for the formation of the conductive regions. An illumination or irradiation through the mask structure follows so that the condition of the regions including the silver-containing additive which can be irradiated through the openings in the mask structure is changed in order to be then especially sensitive to a structure etching. The FOTURAN(copyright) (registered mark) glass of the company Schoft has proven especially advantageous. This material is a photo sensitive material which can be selectively structured in different ways. One starts thereby with a photo structuring. A mask is applied to the photo sensitive glass. The masked glass is subjected to UV irradiation, whereby the regions not covered by the mask react photo chemically. Subsequently, the mask is removed and the glass tempered. Finally, an etching with hydrofluoric acid or the like is carried out, which provides an especially advantageous hole structure. Because of the relatively sharply defined irradiation, the subsequent etching produces holes or openings with relatively sharp and even edges, whereby advantageously absolutely no under-etching takes place. Accordingly, the edges or walls of the openings can be coated relatively well, for example, with the above discussed ITO coating.
Alternatively, it is also possible to equip the first transparent plate, for example, with the conducting regions. A masking of the first plate could hereby also take place whereby material could subsequently be introduced selectively into the first transparent plate to form the conductive regions, by way of a thermal doping or by way of a bombardment with conductive particles in an accelerator.
In order to be able to guarantee the most even surface covering, the feed conductors should have as large an area as possible. Furthermore, the electrodes and counter electrodes respectively should have as large a surface area as possible. By forming the electrodes, the feed conductors to the electrodes, the counter electrodes, and the feed conductors to the counter electrodes with a large surface, it can be guaranteed that the light passing through the light path of an exposure arrangement is treated evenly, so that a disadvantageous influencing of the exposure process is avoided. The electrical resistance of the feed conductors becomes smaller with the larger surface.
When openings are provided in the first plate for connection of the feed conductors to the electrodes, the regular hole structure influences the light during an exposure process. In order to reduce this effect as much as possible, the openings are filled, as much as possible, with a largely transparent filler material, such as a synthetic resin, a putty or the like preferably air free, or without gas enclosures. This is also necessary so that the liquid crystal remains encased.
In order to avoid a negative influence of the light spectrum of a light source in an exposure arrangement on the LCD arrangement according to the invention and especially its liquid crystal fluid, the LCD arrangement can be provided in accordance with the invention with a UV protection. The UV protection is applied to at least one of the plates.
In order to reduce the number of connections to the LCD arrangement in accordance with the invention, respectively two counter electrodes of two adjacent picture elements are supplied through a common feed conductor with signals, especially AC signals (duplex operation). It must thereby be considered that it is especially preferred to equip the LCD arrangement in accordance with the invention with PDLC as liquid crystal fluid, which cannot be exposed to direct current components, since PDLC (Polymer Dispersed Liquid Crystal) components are affected or destroyed by direct current, as are most other materials for LCDs. Accordingly, it is preferred according to the present invention to provide the LCD arrangement with features according to the invention with a PDLC material as liquid crystal fluid. With regard to the PDLC materials, reference is made to Hikmet R.A.M.: xe2x80x9cElectrically induced scattering from anisotropic gelsxe2x80x9d, J. Appl. Phys., Vol. 68 Nr. 9, pages 4406-4412, November 1990, whereby the content thereof is expressly made part of the content of the present disclosure. Individual substances or several of the PDLC substances disclosed therein, also in combination, are incorporated into the present disclosure.
A multiplex operation for the LCD arrangement with features according to the invention is of course also possible, but a duplex operation is preferred, whereby a combination of two respectively adjacent picture elements takes place, whereby two systems of counter electrodes with combined picture elements are used which are controlled with different, for example, complementary signals, for the reduction of the required connections and feed conduits.
In order to guarantee an especially advantageous control of the picture elements of the LCD arrangement in accordance with the invention, they should be constructed in such a way that they can be supplied with binary AC signals. It is important that the voltage difference present across the LC (liquid crystal) is mean value free. Of course, alternating analog signals can also be used here for the control. It is thereby preferred to place signals on the electrodes of the picture elements or the feed conductors which in the transparent condition of the picture elements essentially average out over time or add up to an electric field, the effective value of which is essentially zero or lies below the percolation or correlation limit of the liquid crystal fluid. Otherwise, it is preferred to place signals on the electrodes of the picture elements or their feed conductors which in the non-transparent or light reflecting and/or absorbing condition average out over time or add up to an electric field, the effective value of which is above the percolation or correlation limit of the liquid crystal fluid. With regard to the PDLC materials it is thereby essential that the signals, as already mentioned, are alternating or AC signals. Direct current, or direct voltage components in the control signals for the electrodes of the picture elements are however to be avoided as much as possible.
An especially preferred process, also in view of its simplicity, consists in placing signals on the electrodes of the picture elements which either average out or add up such that the picture elements are transparent, or such that they are not transparent, whereby an amount of light to be passed through per picture element is adjusted over that time over which the picture element is not scattering or scattering.
In order to take into consideration different colour sensitivities of a print material to be exposed, each of the colour ranges for which print material to be exposed has a specific sensitivity can preferably be considered separately, whereby preferably a colour selective filter arrangement is employed. Colour filters can thereby be moved into the light path of the exposure arrangement and for each of the filters an exposure can respectively be carried out, whereby different picture elements can be maintained transparent or non-transparent over specific times, which means for example maintained scattering or non-scattering within a specific temporal relationship.
The process in accordance with the invention for the manufacture of a LCD arrangement with the above listed advantages is based on the following steps: First, a plate, or the first plate, preferably of transparent material, especially FOTURAN(copyright), is provided with an opening mask which is employed for manufacture of the conductive regions or passages. The first plate is then subjected to a material removing treatment in order to form the openings in the first plate. A material which is substantially transparent in the visible range of light is subsequently applied to both sides of the first plate. This material, preferably ITO, is firstly used to form the electrodes of the picture elements of the LCD arrangement and secondly to form the conductive tracks and passages for supply of the control signals to the electrodes. The second plate is coated on one side with ITO and structured for formation of the counter electrodes and subsequently affixed to the first plate, spaced apart parallel thereto. A liquid crystal fluid is then filled into the space between the two plates, preferably PDLC.
The transparent material, preferable ITO, is rendered conductive by way of a heat treatment. The coating material, in the case of ITO, is made transparent after the structuring by way of a heat treatment. Initially after the vapor depositing the thin layer is not transparent, but easily etched (HCL). After the tempering (oxidation), it is transparent but only etched with difficulty (hydrofluoric acid). Otherwise, transparent material could of course also be made conductive by a doping or the like. So could, for example, a completely closed material layer or a glass be used directly and doped superficially such that a transparent property and electric conductivity would only be present in the electrode or conductor regions. For example, a masking coating of aluminum oxide (Al2O3) on a glass substrate, such as FOTURAN(copyright), could be applied to subsequently introduce a temperature initiated doping or a doping based on bombardment with boron ions or the like such that an electrode or conductor structure is produced. This method has then the advantage that an even structure would be present, whereby however a comparatively high doping would be required to provide the required conductivity. In the case of a doping by way of ion bombardment, optical scatter centers could be created which can lead to disruptions.
When the first plate is subjected to the material removing transformation to generate the openings for the conductive regions in the first plate, this can be carried out be way of a reactive processing, for example a dry or wet etching. When FOTURAN(copyright) is used, etching can be carried out by way of hydrofluoric acid.
Conventional vapor deposition or sputtering technology can be used for the application of the material onto the first and/or second plate, whereby this material is essentially transparent in the visible spectrum. When the first plate is being coated, it can be first coated on one side and then on the other. The coating of the both sides can be carried out sequentially, but gripping arrangements with transmissions, for example planetary drives, are available which are able to carry out a complete surface coating. It is thereby essential that the first plate is rotated at an angle to the vapor or sputtering material source, at about an angle of 35 to 60xc2x0, preferably 45xc2x0, in order to coat the openings or their walls, whereby also an edge covering between the plate surface and the walls of the openings is essential. The first plate can thereby also carry out a tumbling movement whereby preferably a mean inclination of 35 to 60xc2x0, especially 45xc2x0, to the vapor or sputtering material source is very advantageous.
As already mentioned above, a cover layer should be applied upon completion of the LCD arrangement according to the invention which is UV reflecting or UV absorbing. This can be in the form of a UV protective glass or in the form of a UV protective foil. After the coating, the openings for the conductive regions in the first plate can be at least essentially filled with at least essentially transparent material. Of course, it is especially advantageous when the openings can be completely filled, since air bubbles or the like can be disadvantageously significant as light scattering centers. A transparent material can thereby be inserted into the openings, heated, and subsequently subjected to a vacuum, so that present or remaining air bubbles can escape because of the low outside pressure.
The UV-reflecting or -absorbing cover layer or the UV-protective glass or the like can be adhered onto the first plate simultaneously with the filling of the openings for the conductive regions using the synthetic resin, putty or the like.
Counter electrodes and feed conductors therefore are formed on the second plate. Since in a preferred embodiment according to the invention a duplex control is maximally possible to achieve the required contrast ratio for the PDLC-LCD arrangements preferred according to the invention, respectively only two picture element electrodes can be controlled with one and the same signal. This allows a reduction to half the number of the required signal feed conductors. For example, for a 20xc3x9730 matrix from 600 to 300. In place of a single counter electrode, two separate counter electrode systems with different, for a duplex operation suitable signals are then to be controlled.
However, it must be pointed out that other processes can of course be used for the manufacture of the openings in the transparent plate. The required openings, for example, can also be achieved by way of a laser.